My next junior project is to build an AlpineStars Cro-Mega LX T26 for my son. Now that we're in the Netherlands, he no longer needs full suspension and the 24" wheels were holding him back. I had a difficult time finding a frame with a low enough standover height for him until I stumbled across this vintage frameset. It uses a 1" threaded rigid fork with a proprietary headset. However, the headtube is an oversize diameter (i.d. is 45mm) and the bearings are of an unusual size. Does anyone know of a semi-integrated headset that will fit into a 45mm headtube so I can install a modern 1 1/8" steerer? I confess, I am bit confused by the variety of headsets out there.

It turns out the inside diameter of the head tube was actually 44mm. I was able to install a semi-integrated headset and use a 1 1/8" fork with no problem. Just waiting for wheels and a few small parts to arrive and then I'll begin building. This will also be a fun project.

The bike is built almost exactly to spec listed above. A couple minor changes. I used Gore sealed cables but only used full-length housing for the rear brake. Tires (currently) are Hutchinson Python UST.

Only one real issue with the bike and that is rear brake setup. The bike is old so was designed for cantilever brakes with the straddle wire running from in front of the seat tube. I set the bike up with Avid SD7 linear pull brakes. There is virtually no clearance between the cable and the top of the tire. I can't run a more aggressive tread in the rear because there is simply no clearance. I may end up putting a cantilever on the back.

The rear end is definitely "noodly." Lots of flex when I wiggle things around back there, but my son weighs less than 70 pounds and doesn't seem to notice it.

It's a bit heavier than I hoped, but there are some places I can save a little weight. For now it is 23.8 pounds (10.8kg) which isn't bad for a vintage steel frame.

I ended up using a BMX crankset, modified to accept a 34t IRD triplizer chainring and a 24t granny. You'll probably notice the tower of spacers on the steer-tube. The head tube is so short I had to use a tall stack to get the handlebar positioned properly. The original fork/steerer/stem/headset combination occupied the same space. I'm reluctant to cut the steerer on this fork because I want to use it on the next frame, or save it for his little brother. If I cut it, it will only work with this frame.

The only bottle cage bosses or under the down tube, right behind the rear tire where the bottle will get covered in mud and other "stuff" on the trail. It's also difficult to reach. So I opted for a stem faceplate bottle cage mount. It's ugly, but it works well. Especially for a little guy. For longer rides he wears a camelback. But the races here tend to be only 30 minutes so one small bottle is enough.

A brake booster will likely do nothing. The rear end of the bike may be flexy, but those stays are burly enough to be doing all the work. I doubt they flex out very much from the cantis. Some vbrakes have longer arms than others, one may clear better than the ones you already tried. Maybe Paul motolite or the cane creek direct curve?

It's a Recon 10-speed cassette. He's been using it for 2 seasons already and it is holding up very well. It shifts perfectly with the Sram drivetrain and KMC X-10sl chain.

Front shifting on the bikes is always challenging due to the very short rear end. I spaced out the bottom bracket a few millimeters to get the chainline right... and also to prevent the front derailleur cage from rubbing on the tire.

The bike performed flawlessly. I'm rather proud of myself. My son raced to a solid 10th place in the rabotop.nl series final. It's only his second race over here (last time he was 15th) and it was his first ride on the bike. So I think he did rather well. The weather was atrocious which made it that much more fun.

The bike was a big hit among all the gearheads too. The combination of vintage and modern parts seemed to be pretty popular. I'm just glad it all worked. Pics to follow.

Who is online

Users browsing this forum: No registered users and 9 guests

You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum